TRENTON — Gun control advocates are going to have to wait longer than they had anticipated for a bill to reduce the permitted size of ammunition magazines to reach Gov. Chris Christie’s desk.

The bill (A2006) is a major piece of unfinished business that those seeking to increase restrictions on firearms began pushing in the wake of the 2012 Newtown, Conn., school shooting.

While the Assembly passed the bill this month, it has not advanced in the state Senate, even though Senate President Stephen Sweeney (D-Gloucester) dropped his previous opposition to it.

Now, gun control advocates concede they’ll probably have to wait until June before the Senate takes it up.

“We were hoping that it would move before now, but it hasn’t,” said Bryan Miller, executive director of the faith-based gun control group Heeding God’s Call. “This has been an incredibly busy time for the Legislature, with all the bridge stuff and everything. I think it’s understandable.”

Miller blamed the delay on Senate discussions about what to do with a companion piece of legislation (A2777), which more clearly defines how gun owners are allowed to transport firearms. The bill was written to mollify gun rights activists who fiercely oppose the ammunition magazine restriction. But they have complained that it is too narrowly written.

The Senate does not plan to take up either bill at its voting session tomorrow, and plans to focus primarily on the state budget until June.

Nevertheless, Miller said he’s “very confident” the magazine restriction bill will be passed.

“It will get done. It’s just a matter of when,” Miller said.

What’s less clear is what will happen when the bill reaches Christie’s desk. Christie has refused to say what he’ll do, but at a town hall he hinted he would not support it by noting that he’s vetoed more bills than any governor since at least the 1940s. Christie also vetoed several gun control measures the legislature sent him last year, including one he had previously called for to ban sales of .50 caliber rifles.